Frustoconical tunnel boring head having radial concave scoops



y 12, 1970 r e. SCHONFELD 3,511,539

FRUSTOCONICAL TUNNEL BORING HEAD HAVING RADIAL CONCAVE SCOOPS Filed July 18, 1969 4 Sheets-Sheet 1 "Fig. 1

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ATTORNEY May 12, 1970 SCHONFEJLD 3,5 1,539

'FRUSTQCONICAL TUNNEL BORING HEAD HAVING RADIAL CONCAVE SCOOPS Filed July 18. 1969 4 Sheecs-Sheet 2 Fig. 5.

GEORG SCHGNFELD INVENTOR.

May 12, 1970 G. SCHONFELD iRUSTOCG-NICAL TUNNEL BORING HEAD HAVING RADIAL CONCAVE SCOOPS Filed July 18, 1969 4 Sheets-Sheet 3 IXVENTOR May 12, 1970 I S'CHQNFELD 3,511,539

FRUSTOCONICAL TUNNEL BORI-NG HEAD HAVING RADIAL CONCAVE SCOOPS 4 Sheets-Sheet 4.

Filed July is; 1969 GEORG SCH5NFELD INVEN TOR.

United States Patent US. Cl. 299-56 7 Claims ABSTRACT OF THE DISCLOSURE Tunnel-boring machine with a generally frustoconical rotary head having a circular front edge spanned by one or more ribs each carrying an array of independently rotatable chisels within the area circumscribed by the front edge, the head further having scoops disposed adjacent the chisels and concave in the direction of rotation for gathering muck and depositing it on a rearwardly extending conveyor passing through a tubular stem of the head slidably lodged in a cylindrical housing which is immobilizable, by a set of radial jacks, with reference to the wall of a tunnel drilled by the boring head. Axially extending thrust jacks on the housing serve for the longitudinal propulsion of the boring head and its stem with reference to the housing whereupon, by means of another set of radial jacks on the head itself, the latter may be immobilized and the housing may be pulled after it upon retraction of the first-mentioned radial jacks. The boring head may be provided with a separable neck which, upon detachment from the head, may be withdrawn from the tunnel together with the housing and with a central drill bit normally projecting beyond the boring head.

This application is a continuation-in-part of my copending application Ser. No. 684,368 filed Nov. 20, 1967.

My present invention relates to a continuous boring machine to be used for excavating underground passages, such as tunnels or adits to mines, or for removing ores, coal or other minerals from subsurface locations.

Recent developments in this field, as described in an article by Thomas E. Howard (Scientific American, November 1967), include a continuous tunnel borer with a cutting or boring head rotating about a substantially horizontal axis, the head carrying a peripheral array of excavating tools working against the tunnel face under the thrust of a set of axially oriented jacks which are mounted in a two-part machine housing. The forward part of the housing, directly behind the head, is immobilized with reference to the tunnel wall by radially oriented jacks (i.e. telescoping legs) during the excavating operation, the rear part of the machine housing being simultaneously pulled forward; thereafter, the rear housing part is similarly immobilized and the front part is released in order to move up to a position just behind the head whereupon the cycle can be repeated.

An object of my present invention is to provide an improved machine of this description which, by virtue of greater compactness, operates more efliciently and is not limited to straight-line advances.

Another important object of this invention is to pro- I machine, minus its boring head, after the excavation of a blind underground passage.

The boring head of a tunneling machine according to the invention is of generally frustoconical, forwardly diverging configuration and is provided at its open front end with a circular cutting edge and with one or more radial sets of excavating tools which are preferably mounted, within the area circumscribed by the cutting edge, on radial ribs spanning this front end. The boring head also carries a plurality of angularly spaced scoops designed to gather the muck or detritus broken loose by the excavating tools and to dump it on a transport device, such as an endless band conveyor, for removal toward the rear through the generally cylindrical machine housing. This arrangement, with the large-diameter machines primarily contemplated herein, still leaves room for maintenance personnel to walk or crawl through the housing for inspection or repair work at the boring site. Advantageously, the excavating tools form a stepped array which slopes forwardly in a radially inward direction; thus, these tools may be rotary chisels independently journaled on respective axes which are parallel to the generatrices of a forwardly converging imaginary cone surface centered on the boring-head axis, the scoops extending forwardly between the tool-supporting ribs so as to terminate in the immediate vicinity of this imaginary cone surface while having their concave sides deepened in the vicinity of the peripheral wall of the boring head to form muck-receiving pockets therewith. The tool-supporting ribs and scoops end short of the boring-head axis to leave free a central area through which a drill bit extends beyond the array of excavating tools; the stem of this drill bit may be rotated jointly with the boring head, or independently thereof, to dig a central channel around which the soil and rock are removed by the revolving tools.

The cylindrical machine housingwhose radius is smaller than that of the array of excavating tools on the boring headadvantageously consists of a single part fitted with a first set of radial jacks for immobilizing the housing during the forward thrust of the head, another set of radial jacks being provided on the head itself whereby, upon extension of the latter jacks and retraction of the former, a reversal of the thrust-exerting plungers of an axial jack assembly pulls the housing into the tunnel after the now immobilized boring head. The latter can then again be fixed in position whereupon, after retraction of the boring-head jacks, a new forward thrust may be exerted upon the array of excavating tools. With this arrangement, given two axially spaced and independently operable sets of radial jacks on the machine housing, the latter can be limitcdly tilted in any direction so that the boring head may be steered to follow the course of a coal vein or otherwise advance on a path deviating from a straight line.

By providing the boring head with a separable neck, I am able to extract the machine housing, the drill bit and the conveyor from the tunnel in a rearward direction if, for any reason, the tunnel is to remain as a blind underground passage; in this case, only the boring head with its chisels and picks is lost.

The invention will be described in greater detail with reference to the accompanying drawing in which:

FIG. 1 is a sectional elevational view of a tunnelboring machine according to the invention, shown in its position of forward thrust;

FIG. 2 is partly an end view and partly a crosssectional view taken on the line IIII of FIG. 1;

FIG. 3 is a side-elevational view of the machine in a position of deviation from a straight line;

FIG. 4 is a cross-sectional view taken on the line IVIV of FIG. 3;

FIG. 5 is a detail view, drawn to a larger scale, of one of the excavating tools on the boring head of the machine; and

FIGS. 6 and 7 are enlarged side-elevational views of other forms of excavating tools usable with the machine of FIGS. l-4.

The machine shown in FIGS. 14 comprises a funnelshaped boring head, generally designated 1, having a frustoconical peripheral wall 4 whose open front end 4a, diverging at a smaller vertex angle, terminates in a circular cutting edge 41;. Extension 4a is spanned by a set of ribs 3 serving as carriers for an array of cutting tools 2; in the specific embodiment illustrated, four such ribs extend in respective radial planes 90 apart (see FIG. 2). The ribs 3 slope forwardly, ie, to the left in FIG. 1, toward the axis of rotation O of head 1 and terminate short of this axis at a central tube 5 which gives passage to a shaft 30 of a drill bit 7 projecting forwardly beyond the array of excavating tools 2. The latter tools are mounted in a stepped formation on the ribs 3, within the area circumscribed by the circular edge 4b,. so that their leading edges are tangent to the generatrices of an imaginary conical surface bounded by the edge 4b and substantially coincident with the tunnel face T being shaped by these tools. In the embodiment of FIG. 1, and as more clearly shown in FIG. 5, the tools 2 are rotary chisels provided with annular cutting ridges 31 and journaled on individual bolts 6 whose axes are more or less parallel to the associated ribs 3, on which the studs are mounted by brackets 27, and to the generatrices of the aforementioned imaginary surface represented in FIG. 1 by the tunnel face T. Thus, rotation of head 1 about its axis will cause the chisels 2 to roll on the tunnel face T' while biting ever more deeply into the soil around the central channel C produced by the bit 7.

The axial staggering of the leading edges of chisels 2 results in a terracing of the tunnel face, as best seen in FIG. a set of scoops 8, whose for-ward edges 8' extend parallel to ribs 3 in the immediate vicinity of the leading edges of chisels 2, help smooth the stepped tunnel face shown in FIG. 5 and also collect the rubble or muck provided by the chisels which drops onto the rotating apron 4a; toward the rear, the concave sides of the scoops 8 facing in the direction of rotation (counterclockwise in FIG. 2) are deepened so as to form pockets 9 with the frustoconical wall 4 of head 1. These pockets discharge, as each scoop swings above the median horizontal plane of the boring head 1, onto a conveyor 10 shown as an endless belt led around a forward roller 11 and a rear roller not shown. Belt 10 is driven, by means not further illustrated, in the direction of arrow A so as to transport the deposited detritus toward the rear from the region of head 1. The rollers are journaled between cantilevered, axially shiftable bars 32 so that the conveyor may be withdrawn from the head for purposes of access, inspection or repair; shaft 30 of bit 7 may be similarly retractable through tube 5.

A set of webs 33, respectively aligned with ribs 3, extend from tube 5 rearwardly to the narrow base of the truncated cone 4 to form supports for respective jacks 26 passing radially outwardly through the cone wall. This wall 4 is received in a frustoconical neck 34 with which it is coupled for joint rotation by a set of axial pins 35 and which is rigid with a horizontal tube 12 surrounding the shaft 30 and the conveyor 10. Tube 12 is rotatably journaled, with the aid of interposed bearings 36, in a machine housing comprising two nested cylinders 15, 16 which define an annular space 17 centered on axis 0. This space accommodates the cylinders 38, 39 of two axially spaced radial arrays of jacks 18 and 19, two pairs of diametrically aligned jacks being provided in each array as illustrated in FIGS. 3 and 4. In addition, the

cylinders 20 of an array of axially extending jacks 22, centered on axis 0, are also mounted in the space 17 along with conduits 37 for reversibly displacing these jacks, the conduit system including a reversing valve 40 which may be oscillated at a rapid rate to impart an intermittent forward thrust to the jacks 22 and through them to a ring 23 which presses through needle bearings 25 upon an annular shoulder 24 of neck 34. A flanged outer ring 41 embraces ring 23 to insure that a reverse actuation of jacks 22 will not disengage these jacks from the neck 34 of boring head 1. The head is furthermore shown provided with tie rods 42, e.g. three of them spaced apart, by which it is removably fastened to the tube 12 so as to maintain the structural unity of elements 1, 34 and 12. Upon disconnection of rods 42 from tube 12, housing 15, 16 with its jacks 18, 19 and 22 as well as tube 12 and neck 34 may be withdrawn from the tunnel without any interference from the coupling pins 35, leaving the head 1 in place as a lost implement.

Rotation is imparted to head 1 by means of one or more motors 43 mounted in the housing space 17, each of these motors driving a pinion 44 in mesh with a ring gear 21 which is rigid with tube '12. Bit 7 may be rotated in step with head 1, through a suitable coupling not shown, or independently thereof by drive means not further illustrated.

As shown in FIGS. 6 and 7, chisels 2 may be replaced by chisels 2' or 2" having a single helicoidal cutting ridge 28 or a pair of such ridges 29. Moreover, as illustrated'in FIG. 2, additional chisels 14 may be disposed on the inner periphery of cone 4 between the arrays of tools 2.

In the normal operation of the system shown in FIGS. 1-4, with jacks 22 and 26 initially retracted and jacks 18 and 19 extended as illustrated in FIG. 1, bit 7 and head 1 are rotated to drill the channel C and to excavate the tunnel face T. During this operation, hydraulic or pneumatic fluid is admitted to the cylinders 20 to drive the head 1 continuously forwardly to the limit of the stroke of jacks 22. Conveyor 10 removes the oncoming debris, advancing together with head 1, shaft 30 and tube 12.

When the end of the stroke of the axial jacks 22 has been reached, the drive 43, 44, 21 of head 1 is arrested, fluid is admitted to the cylinders of jacks 26 through conduits not illustrated to extend these jacks radially outwardly against the tunnel wall whereby the head 1 is immobilized, and jacks 18, 19 are retracted whereupon valve 40 reverses the connections of cylinders 20 so that these cylinders are drawn forwardly with reference to the now stationary pistons 22. By this action, with cylinder 15 sliding on tube 12, housing 15, 16 is again brought into close juxtaposition with head I whereupon the aforedescribed cycle may be repeated with extension of jacks 18, 19, retraction of jacks 26 and forward actuation of jacks 22 while rotation of head 1 is resumed. If this actuation of jacks 22 occurs intermittently as set forth above, as by a rapid alternation of relatively long forward thrusts with relatively short reverse movements, the fragmentizing effect of the cutting tools 2 will be enhanced.

FIGS. 3 and 4 illustrate the manner in which my improved system can be used to dig tunnels departing from straight linearity. To this end it is merely necessary that two diametrically opposite jacks of the machine housing, e.g. jacks 18a, 18b of the forward array of jacks 18, be left extended during continuing rotation of head 1 so as to form a pivotal axis P for the swing of housing 15, 16 under the control of jacks 19c, 19d of the rear array which stand skew to the extended jacks 18a, 18b. The other jacks 18c, 18d of the front array and the remaining pair of jacks of the rear array, all operable independently, are then extended beyond the tunnel wall to lock the machine housing in its tilted position; the boring operation then resumes as previously described. Tilting angles up to 45 can be readily achieved with this technique, especially if the end plates 18, 19' of the jacks are pivotally mounted on their pistons through suitable universal joints; such joints have been illustrated at 45, FIG. 1, for the end plates 26' of jacks 26.

I claim:

1. A tunnel-boring machine comprising a generally cylindrical housing; a generally frustoconical, forwardly diverging boring head supported on said housing for rotation about a substantially horizontal axis, said boring head having an open front end and tool-supporting means spanning said front end; an array of excavating tools on said tool-supporting means, said array extending over a radius greater than that of said housing; a plurality of scoops on said boring head, said scoops extending generally radially inwardly from the periphery of said boring head at angularly spaced locations and being concave in the direction of rotation of said head; and transport means on said housing for removing muck broken loose by said tools and picked up by said scoops.

2. A tunnel-boring machine as defined in claim 1 wherein said front end is provided with a circular cutting edge having a radius substantially equal to that of said array, said tool-supporting means comprising a plurality of peripherally spaced radially extending ribs inside said cutting edge, said scoops being disposed between said ribs within an area circumscribed by said cutting edges.

3. A tunnel-boring machine as defined in claim 2 wherein said ribs terminate short of a central area of said boring head, further comprising a central drill bit projecting axially beyond said boring head through said central area.

4. A tunnel-boring machine as defined in claim 2 wherein said tools have leading edges tangent to a forwardly converging imaginary cone surface centered n said axis and bounded by said cutting edge, said scoops extending forwardly to substantially said imaginary cone surface.

5. A tunnel-boring machine as defined in claim 4 wherein the concave sides of said scoops are deepened in the vicinity of the peripheral wall of said boring head whereby pockets for said muck are formed between said scoops and said peripheral wall.

6. A tunnel-boring machine as defined in claim 4 wherein said tools are rotary chisels with generally annular cutting ridges mounted for independent rotation about axes substantially parallel to said cone surface.

7. A tunnel-boring machine as defined in claim 6 wherein said cutting ridges are of helicoidal shape.

References Cited UNITED STATES PATENTS 1,720,195 7/1929 App 29990 X 2,837,325 6/1958 Biedess 2-99-90 X 3,232,670 2/1966 Robbins et al. 299--56 FOREIGN PATENTS 934,996 8/1963 Great Britain.

ERNEST R. PURSER, Primary Examiner US. Cl. X.R. 299-31, 90 

